import java.util.Scanner;

/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: 晓星航
 * Date: 2023-02-20
 * Time: 14:38
 */

public class TestDemo {
    public static String func(String str) {
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if (!sb.toString().contains(ch+"")) {
                sb.append(ch);
            }
        }
        return sb.toString();
    }
    public static String func2(String str) {
        StringBuilder sb = new StringBuilder();
        int[] array = new int[58];
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if (array[ch - 65] == 0) {
                sb.append(ch);
                array[ch - 65] = 1;
            }
        }
        return sb.toString();
    }

    public static String qiqi(String str) {
        StringBuilder sb = new StringBuilder();
        int[] array = new int[127];
        for (int i = 0; i < str.length(); i++) {
            char ch = str.charAt(i);
            if (array[ch] == 0){
                sb.append(ch);
                array[ch] = 1;
            }
        }
        return sb.toString();
    }
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNextLine()) {
            String str = scanner.nextLine();
            String ret = qiqi(str);
            System.out.println(ret);
        }
    }
    public static void main3(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNextLine()) {
            String str = scanner.nextLine();
            String ret = func2(str);
            System.out.println(ret);
        }
    }
    public static void main2(String[] args) {
        Scanner scanner = new Scanner(System.in);
        while(scanner.hasNextLine()) {
            String str = scanner.nextLine();
            String ret = func(str);
            System.out.println(ret);
        }
    }
    public static void main1(String[] args) {
        String foo1 = args[1];
        String foo2 = args[2];
        String foo3 = args[3];
    }
}
